The geodynamic origin of Los Humeros volcanic field in Mexico: insights from numerical simulations.

Compared to normal arc-related volcanic eruptions, the formation of a volcanic caldera is a relatively atypical event. During caldera formation a series of large volumes of magma are erupted, reducing the structural support for the rock above the magma chamber and creating a large depression at the surface called caldera. Los Humeros volcanic field (LHVF) represents one of the largest volcanic calderas in Mexico. It is located some 400 km from the trench at the eastern edge of the Trans Mexican Volcanic Belt where the depth to the Cocos slab is more than 300 km. In this study we employ high-resolution two-dimensional thermomechanical numerical simulations of magma intrusions and a horizontal tectonic strain rate to better understand the influence of crustal deformation for the formation of Los Humeros caldera. A minimum number of three thermal anomaly pulses of hydrated mantle material (with diameter of 15 km or more) and a regional strain rate of 7.927 × 10-16 s-1 are required for magma to reach the surface. Modeling results show that regional extension coupled with deep thermal anomalies (with a temperature excess of ΔT ≥ 100 °C) that come in a specific chain-type sequence produce surface deformation patterns similar to LHVF. We propose an asthenospheric sub-slab deep source (> 300 km depth) for the thermal anomalies where previous studies showed the existence of a gap or tear in the Cocos slab.

Evolutionary dynamics of autopolyploids in natural populations: the case of Turnera sidoides complex / Dinámica evolutiva de autopoliploides en poblaciones naturales: el caso del complejo Turnera sidoides

ABSTRACT Turnera sidoides (x=7) is one of the few well-studied South American autopolyploid complexes. Since polyploidy has played a prominent role within this complex, ongoing studies in T. sidoides focus on understanding the mechanisms involved in the origin and the establishment of polyploids using integrative approaches. This paper synthesises the results of more than 20 years of research on this topic. Cytogenetics analysis provided evidences for the production of unreduced male and female gametes, supporting the hypothesis of bilateral sexual polyploidization as the mechanism of origin of polyploids in T. sidoides. The finding of viable triploids suggested that unilateral sexual polyploidization could also be an important mechanism for the origin of tetraploids in T. sidoides. The occurrence of plants continuously forming many unreduced gametes would play a key role in the establishment of neopolyploids in natural populations. Also, the higher number of propagules that tetraploids contribute to subsequent generations, the ability to multiply asexually by rhizomes, and the occurrence of occasional cases of self-compatibility and successful illegitimate crosses in polyploids increase the likelihood that a low frequency of neopolyploids can be maintained in natural populations of T. sidoides. In addition, integration of cytogeographic and genetic divergence data together with past niche modelling provided further insights supporting the hypothesis that historical climatic and geomorphological events provided favourable conditions for the establishment of autopolyploids, with the wider distribution of tetraploids of T. sidoides being the result of their range expansion.

RESUMEN Turnera sidoides (x=7) es uno de los pocos complejos autopoliploides sudamericanos bien estudiados. Como la poliploidía ha tenido un papel destacado en el complejo, los estudios en curso en T. sidoides se centraron en la comprensión de los mecanismos implicados en el origen y el establecimiento de los poliploides mediante diferentes enfoques. En este trabajo se sintetizan los resultados de más de 20 años de investigación sobre este tema. El análisis citogenético proporcionó evidencias de la producción de gametos masculinos y femeninos no reducidos, sustentando la hipótesis de la poliploidización sexual bilateral como mecanismo de origen de los poliploides en T. sidoides. Sin embargo, el hallazgo de triploides fértiles sugirió que la poliploidización sexual unilateral también sería un mecanismo importante de origen de tetraploides en T. sidoides. La ocurrencia de plantas que forman continuamente gametos no reducidos desempeñaría un papel clave en el establecimiento de neopoliploides. Además, el mayor número de propágulos que los tetraploides aportan a las siguientes generaciones, la capacidad de multiplicación asexual por rizomas y los casos ocasionales de autocompatibilidad y cruzamientos ilegítimos exitosos aumentarían la probabilidad de que se mantenga una baja frecuencia de neopoliploides en las poblaciones naturales de T. sidoides. Asimismo, la integración de datos citogeográficos y de divergencia genética junto con el modelado de nicho en el pasado aportó información que sustenta la hipótesis de que los eventos climáticos y geomorfológicos históricos proporcionaron las condiciones favorables para el establecimiento y expansión de los tetraploides de T. sidoides.

Experimental assessment of performance and emissions for hydrogen-diesel dual fuel operation in a low displacement compression ignition engine.

The combustion of pure H2 in engines is still troublesome, needing further research and development. Using H2 and diesel in a dual-fuel compression ignition engine appears as a more feasible approach. Here we report an experimental assessment of performance and emissions for a single-cylinder, four-stroke, air-cooled compression ignition engine operating with neat diesel and H2-diesel dual-fuel. Previous studies typically show the performance and emissions for a specific operation condition (i.e. a fixed engine speed and torque) or a limited operating range. Our experiments covered engine speeds of 3000 and 3600 rpm and torque levels of 3 and 7 Nm. An in-house designed and built alkaline cell generated the H2 used for the partial substitution of diesel. Compared with neat diesel, the results indicate that adding H2 decreased the air-fuel equivalence ratio and the Brake Specific Diesel Fuel Consumption Efficiency by around 14-29 % and 4-31 %. In contrast, adding H2 increased the Brake Fuel Conversion Efficiency by around 3-36 %. In addition, the Brake Thermal Efficiency increased in the presence of H2 in the range of 3-37 % for the lower engine speed and 27-43 % for the higher engine speed compared with neat diesel. The dual-fuel mode resulted in lower CO and CO2 emissions for the same power output. The emissions of hydrocarbons decreased with H2 addition, except for the lower engine speed and the higher torque. However, the dual-fuel operation resulted in higher NOx emissions than neat diesel, with 2-6 % and 19-48 % increments for the lower and higher engine speeds. H2 emerges as a versatile energy carrier with the potential to tackle current energy and emissions challenges; however, the dual-fuel strategy requires careful management of NOx emissions.

[Risk of refracture according to the FRAX score in patients older than 50 years who suffer a fracture by a low-impact mechanism]. / Riesgo de refractura según el FRAX score en pacientes mayores de 50 años que sufren una fractura por un mecanismo de bajo impacto.

INTRODUCTION: as the population pyramid inverts, we'll see more old patients suffering a fracture secondary to a low impact mechanism and not all hospitals have a densitometer to make a definitive diagnosis. Nevertheless, we have clinical tools that can help us to start an early treatment. OBJECTIVE: to recognize the risk of re-fracture of patients older than 50 years in our population. MATERIAL AND METHODS: we included all patients older than 50 that suffered a low impact fracture in the Ángeles Mocel Hospital. We used Mexico FRAX score tool to determine de risk of suffering a fracture. The sample was divided in two groups. Utilizing p < 0.05 and a CI of 95%. RESULTS: 69 patients where included. 47.8% had past fractures and only 10% of those had preventive osteoporotic treatment. 50.7% of the patients have a high risk of suffering a mayor osteoporotic fracture in 10 years and 75% of suffering a hip fracture in 10 years. None of the patients received a treatment, either lifestyle modifiers or specific osteoporosis pharmacotherapy at hospital discharge. CONCLUSION: there is a deficiency in the early preventive management of osteoporosis in patients suffering a low impact fracture by orthopedic surgeons.

INTRODUCCIÓN: a medida que se invierte la pirámide poblacional vamos a ver más pacientes que sufren fracturas por mecanismos de bajo impacto y no todos los hospitales cuentan con un densitómetro para hacer el diagnóstico definitivo. Sin embargo, se cuenta con herramientas clínicas que nos apoyan para iniciar con un tratamiento oportuno. OBJETIVO: reconocer el riesgo de refractura que existe en pacientes mayores de 50 años dentro de nuestra población. MATERIAL Y MÉTODOS: se incluyeron a pacientes > 50 años que sufrieron de una fractura de bajo impacto en el Hospital Ángeles Mocel. Usando el FRAX score México para medir el riesgo de sufrir una fractura. Se dividió la muestra en dos grupos, utilizando una p < 0.05 para considerar estadísticamente significativa con un IC de 95%. RESULTADOS: se incluyeron 69 pacientes, 47.8% ya habían sufrido de alguna fractura previa, 10% de ellos tienen tratamiento para la osteopenia. El riesgo de sufrir una fractura mayor osteoporótica en 10 años se observó en 50.7% de los pacientes. El riesgo de sufrir una fractura de cadera en 10 años se encontró en 75% de los pacientes. A ningún paciente se le dio tratamiento, ya sea modificadores del estilo de vida o tratamiento farmacológico para osteopenia/osteoporosis a su egreso hospitalario. CONCLUSIÓN: hay una deficiencia en el manejo inmediato de los cirujanos ortopedistas para prevenir en pacientes futuras refracturas de bajo impacto.

Occurrence, distribution and dynamics of perchlorate in soil, water, fertilizers, vegetables and fruits and associated human exposure in Chile.

Perchlorate (ClO4-) has been identified as a persistent environmental contaminant of concern. Perchlorate exposure is a potential health concern because it interferes with hormone production by thyroid gland. Food (fruits and vegetables) and drinking water are an important source of human exposure to perchlorate. However, little is known about the occurrence of perchlorate in Chile. The purpose of this study was to determine the occurrence of perchlorate in 145 samples (soil, drinking water, surface water, groundwater, fertilizers, fruits and vegetables) collected across Chile and estimate associated exposure to consumers. Our results show that perchlorate was detected in soil (median: 22.2 ng g-1), drinking water (median: 3.0 ng mL-1), fruits (median: 0.91 ng g-1 fresh weight [FW]), lettuce (median: 5.0 ng g-1 FW) and chard (median: 4.15 ng g-1 FW). Interestingly, perchlorate concentrations detected in drinking water from three regions (Serena, Copiapo and Illapel) exceeded the USEPA interim drinking water health advisory level of 15 ng mL-1. Median concentrations of perchlorate in non-nitrogenous fertilizers (3.1 mg kg-1) were higher than those in nitrogenous fertilizers (1.3 mg kg-1). Estimated daily intake (EDI) of perchlorate via drinking water was lower than the USEPA's reference dose (7000 ng kg-1 bw day-1). The EDI of perchlorate via vegetables (chard and lettuce) produced in northern Chile was three times higher than those produced in other regions. The results of this study provide information about perchlorate sources in Chile, which will be helpful in modifying current regulations.

[Computer-assisted total bilateral knee arthroplasty in one surgical time]. / Artroplastía total de rodilla bilateral en un tiempo quirúrgico asistida por computadora.

INTRODUCTION: Total navigated knee replacement uses a computer-guided system, which provides immediate information on pre-cut trans-operative conditions of the knee, in relation to pelvic limb alignment. MATERIAL AND METHODS: Observational, descriptive study conducted from March 2003 to February 2019. Total bilateral knee replacement was performed at the same time surgically by a surgeon, evaluating function and pain on the WOMAC, EVA, and range of motion scores of both knees. Two groups of patients were studied: the first represents presurgical and the second post-surgical. Student's t-test and 2 were applied for statistical analysis. RESULTS: 31 patients (62 prostheses), 83.9% of the female sex and 16.1% male, average age 67.32 years, average follow-up 6.55 years (± 3.8) were studied. It was identified that 100% of the patients in both knees have a deviation between 0o and 2o measured in the mechanical axis. The WOMAC scale showed an average of 22.71 ± 3.34 presurgical and 4.16 ± 1.84) post-surgical, with statistically significant differences. The average analog visual scale was 9.06 ± 0.814 presurgical and 2.35 ± 1.427 post-surgical. CONCLUSIONS: This technique is reliable, safe and satisfactory. Excellent clinical and radiographic results were evident regarding the positioning of prosthetic components.

INTRODUCCIÓN: La artroplastía total de rodilla navegada utiliza un sistema guiado por computadora que proporciona información inmediata de condiciones transoperatorias precorte de la rodilla, con relación a la alineación del miembro pélvico. MATERIAL Y MÉTODOS: Estudio observacional, descriptivo, efectuado de Marzo de 2003 a Febrero de 2019. Se realizó artroplastía total de rodilla bilateral navegada en un mismo tiempo quirúrgico por un cirujano, evaluando función y dolor según las escalas WOMAC, EVA y arcos de movilidad de ambas rodillas. Se estudiaron dos grupos de pacientes: el primero representa prequirúrgicos y el segundo postquirúrgicos. Se aplicó prueba t de Student y 2 para el análisis estadístico. RESULTADOS: Se estudiaron 31 pacientes (62 prótesis), 83.9% del sexo femenino y 16.1% del masculino, edad media 67.32 años, media de seguimiento 6.55 años (± 3.8). Se identificó que 100% de los pacientes intervenidos en ambas rodillas tienen una desviación entre 0o y 2o medida en el eje mecánico. La escala WOMAC mostró una media de 22.71 ± 3.34 prequirúrgica y 4.16 ± 1.84 postquirúrgica, con diferencias estadísticamente significativas. La escala visual análoga media fue de 9.06 ± 0.814 prequirúrgico y 2.35 ± 1.427 postquirúrgico. CONCLUSIONES: Esta técnica es confiable, segura y satisfactoria. Se evidenciaron excelentes resultados clínicos y radiográficos respecto al posicionamiento de los componentes protésicos.

Diseño y validación de material didáctico para una intervención educativa de enfermería en cuidadores primarios / Design and validation of didactic materials for a nursing educational intervention to primary caregivers / Desenho e validação de material didático para uma intervenção educativa de enfermagem em cuidadores primários

Resumen Introducción: El cuidador es una persona que en sí misma requiere cuidado, existe poca evidencia sobre la validación de material dirigido a cuidadores primarios de adultos en el domicilio. Objetivo: Diseñar y validar el material didáctico de apoyo en una propuesta de intervención educativa de enfermería para mejorar el autocuidado de cuidadores primarios de personas con enfermedades crónicas no transmisibles. Material y Métodos: Investigación metodológica para validación de diez carteles. Evaluación por cuatro expertos y diez cuidadores primarios. La investigación se desarrolló en cuatro fases: a) valoración de las necesidades en salud y determinación de los contenidos, b) elaboración de material didáctico, c) jueceo y validación técnica, d) validación con población. Se evaluaron los aspectos de atracción, comprensión, involucramiento y aceptación con un cuestionario dicotómico de ocho preguntas por cartel. Se calculó el coeficiente V de Aiken como indicador de aprobación. Se tomó el valor de 0.7 y superior como punto para la validación. Resultados: En la primera ronda de evaluación por los expertos se modificaron tres carteles por su bajo coeficiente de comprensión-atracción y se reelaboró un cartel. En la segunda versión de los carteles se alcanzaron coeficientes superiores a 0.81. Sin embargo, los cuidadores puntuaron dos carteles con valores inferiores al estándar, por lo que luego de tomar su opinión al respecto se modificaron aspectos de diseño. Discusión: Las recomendaciones de los expertos en el área y particularmente los intereses de los cuidadores primarios fueron la base para mejorar el diseño del material didáctico. Conclusiones: Tras ajustar elementos de la atracción y comprensión de los carteles se concluyó que el Material Didáctico (MD) es adecuado para su implementación en una Intervención Educativa (IE) dirigida a mejorar el autocuidado de cuidadores primarios.

Abstract Introduction: Caregivers are persons who themselves also need care, and there is few evidence regarding the validation of educational materials for caregivers of adult home care. Objective: To design and validate supporting didactic materials for a nursing educational intervention proposal in order to improve self-care among primary caregivers attending patients with non-transmissible chronic illnesses. Materials and Methods: This is a validating research study using 10 educational materials which were assessed by 4 field experts and 10 primary caregivers. The research study was developed in four stages: a) assessment of the health needs and determination of the contents for the education materials, b) elaboration of the education materials, c) technical validation, d) assessment on the use in a population. Features of attractiveness, comprehension, involvement, and acceptance were estimated using a dichotomous questionnaire of 8 questions for each educational material. The Aiken V coefficient of approval was calculated. Values greater than 0.7 were considered as valid results. Results: In the first round of assessment by the experts, three educational materials were modified due to their low coefficient of comprehension-attractiveness and one education material was redesigned. The subsequent version of the education materials showed coefficients higher than 0.81, however, caregivers gave two materials scores below the standard, and these materials were further redesigned. Discussion: The recommendations from the experts in the field, along with the interests of the primary caregivers, were the base to improve the design of the didactic materials. Conclusions: After adjusting elements related to the attractiveness and comprehension of the didactic materials, it was concluded that the redesigned materials were adequate for an educational intervention aimed at improving self-care among primary caregivers.

Resumo Introdução: O cuidador é uma pessoa que em si mesmo requer de cuidado, há pouca evidência sobre a validação de material dirigido aos cuidadores primários de adultos no domicílio. Objetivo: Desenhar e validar o material didático de apoio em uma proposta de intervenção educativa de enfermagem para melhorar o autocuidado de cuidadores primários de pessoas com doenças crônicas não transmissíveis. Material e Métodos: Pesquisa metodológica para validação de dez pôsteres. Avaliação por quatro especialistas e dez cuidadores primários. A pesquisa desenvolveu-se em quatro fases: a) avaliação das necessidades de saúde e determinação dos conteúdos, b) elaboração do material didático, c) julgamento e validação técnica, d) validação com população. Avaliaram-se os aspectos de atração, compreensão, envolvimento e aceitação com um questionário dicotômico de oito perguntas por pôster. Foi calculado o coeficiente V de Aiken como indicador de aprovação. Tomou-se o valor de 0.7 e superior como ponto para a validação. Resultados: Na primeira rodada de avaliação dos especialistas modificaram-se três pôsteres por seu baixo coeficiente de compreensão-atração e foi reelaborado um pôster. Na segunda versão dos pôsteres foram alcançados coeficientes superiores a 0.81. Porém, os cuidadores pontuaram dois pôsteres com valores inferiores ao padrão, portanto, após se manifestarem sobre o assunto modificaram-se aspectos de desenho. Discussão: As recomendações dos especialistas da área e particularmente, os interesses dos cuidadores primários foram a base para melhorar o desenho do material didático. Conclusões: Após ajustar elementos da atração e compreensão dos pôsteres foi concluído que o MD é adequado para sua implementação em uma IE dirigida a melhorar o autocuidado de cuidadores primários.

Sources and fates of perchlorate in soils in Chile: A case study of perchlorate dynamics in soil-crop systems using lettuce (Lactuca sativa) fields.

Perchlorate occurs naturally in the environment in deposits of nitrate and can be formed in the atmosphere and precipitate into soil. However, little is known about the occurrence and levels of perchlorate in soils and fertilizers in Chile and its impacts on agricultural systems and food safety. In this study, concentrations of perchlorate were determined in 101 surface soils and 17 fertilizers [nitrogenous (n = 8), nitrogen-phosphorous-potassium (NPK; n = 3), phosphate (n = 2) and non-nitrogenous (n = 4)] collected across Chile from 2017 to 2018. Our results show that perchlorate was detected mainly in agricultural soils (mean: 0.32 ng g-1), grassland rotation sites (0.41 ngg-1) and urban locations (0.38 ng g-1). Interestingly, elevated concentrations of perchlorate (9.66 and 54.0 ng g-1) were found in agricultural soils. All fertilizers contained perchlorate: nitrogenous fertilizers (mean: 32.6 mg kg-1), NPK (mean: 12.6 mg kg-1), non-nitrogenous fertilizers (mean: 10.2 mg kg-1) and phosphates (mean: 11.5 mg kg-1). Only one type of nitrogenous fertilizer (KNO3: 95.3 mg kg-1) exceeded the international regulation limit (50 mg kg-1). For two agronomic practices, the content of perchlorate in lettuce increased as the fertilizer application rate increased, with fertigation promoting a more significant accumulation. However, the concentrations generally remained below regulatory values. Our results suggest that fertilizers constitute an important source of perchlorate in soils.

Epigenetic regulation of folate receptor-α (FOLR1) in human placenta of preterm newborns.

INTRODUCTION: Folates are essential nutrients for fetal development and pregnancy outcomes; they are transported to the fetus during gestation through specific folate transporters located in the placenta. In preterm newborns, we previously showed a lower placental mRNA expression of FOLR1 along with higher folate and lower vitamin B12 cord blood levels. Thereby we aimed to explore FOLR1 methylation in placentas of preterm newborns and hypothesized an increased FOLR1 methylation associated with cord blood folates and vitamin B12 concentrations. METHODS: FOLR1 methylation and mRNA were determined by methylation sensitive - high resolution melting (MS-HRM) and by real-time PCR respectively, in two placental sides of placental tissues: maternal (basal, BP) and fetal plates (chorionic, CP) of moderate preterm infants (32-36 gestational age) and term birth (37-41 gestational weeks). Folates and vitamin B12 were determined by electrochemiluminescence in umbilical cord blood samples from term and preterm newborns. RESULTS: We found that in preterm newborns, FOLR1 mRNA was lower in both plates of placenta compared with term newborns (p < 0,05) and was negatively associated with methylation of FOLR1 in CP. Preterm newborns presented higher folate and lower vitB12 concentrations in cord blood which correlated with increased placental FOLR1 methylation. DISCUSSION: In preterm newborns, placental FOLR1 expression is regulated by epigenetic mechanisms and presumably by maternal concentrations of folate and vitamin B12.

The impact of pregnancy on the outcome of biliary acute pancreatitis. / El impacto del embarazo en el desenlace de pancreatitis biliar aguda.

BACKGROUND AND OBJECTIVE: Acute pancreatitis is one of the most common gastrointestinal conditions requiring hospitalization. Even though its presentation during pregnancy is uncommon, it is a medical challenge. Currently, no studies compare the clinical outcomes between pregnant patients with acute pancreatitis and nonpregnant patients with acute pancreatitis. Our aim was to compare the characteristics and clinical outcomes of pregnant and nonpregnant women with acute pancreatitis. METHODS: We conducted a retrospective study that included all patients admitted to our hospital with acute pancreatitis over a 10-year period. Demographics, general characteristics, and clinical outcomes were evaluated and compared between pregnant and nonpregnant women with acute pancreatitis, at a ratio of 1:5. RESULTS: Over 10 years, 27 pregnant patients with acute pancreatitis were treated. Etiology was biliary in 96% and hypertriglyceridemia was the cause in 3.4% (1 patient). The mean patient age was 26.2 years (range 15-36 years). The main cause of acute pancreatitis was biliary disease (96%). Patients in the study group were in their first, second, or third trimester of pregnancy, at 7.4%, 33.3%, and 59.3%, respectively. In the comparison of pregnant versus nonpregnant patients with acute pancreatitis, there were no differences in age, hospital stay (7.37 vs. 10.8, P=.814), severity (severe 3.7% vs. 16.7%, P=.79), local complications (0% vs. 1.9%, P=.476), or mortality (0% vs. 1.9%, P=.476). CONCLUSIONS: The clinical evolution of both groups with biliary acute pancreatitis was similar, with low morbidity and mortality.

Field study on the uptake, accumulation and risk assessment of perchlorate in a soil-chard/spinach system: Impact of agronomic practices and fertilization.

The application of excessive fertilizer represents a primary source of entry for perchlorate into crop systems and thus has raised widespread concern regarding food safety. Several studies have reported the occurrence of perchlorate in vegetables. However, limited information is available on the fate of perchlorate in the soil-plant system. In this study, we performed field experiments to evaluate the effects of the application rate of Chilean nitrate fertilizer and the type of fertilization (manual or fertigation) on the uptake of perchlorate by plants grown in open fields. Interestingly, in the control, chard and spinach accumulated 21.3 and 25.9 µg kg-1, respectively. For both agronomic practices, the content of perchlorate in chard and spinach increased as the fertilizer application rate increased, with fertigation promoting more significant accumulations. Spinach accumulated almost two times more perchlorate than chard for all treatments; however, the concentrations generally remained below regulatory values. The intake of spinach and chard presented a low risk to human health for all age groups. These findings enhance our understanding of the environmental impact of the use of fertilizers in agriculture and food safety.

When the Ice Has Gone: Colonisation of Equatorial Glacier Forelands by Ground Beetles (Coleoptera: Carabidae).

Ground beetles (Coleoptera: Carabidae) are among the early colonisers of recently deglaciated terrains. While patterns of carabid colonisation along forelands of retreating glaciers have been thoroughly investigated in temperate climates, information remains scarce in tropical mountains. This study aimed to describe for the first time the carabid beetle species assemblages along the chronosequence of two tropical Andean glaciers (Antisana and Carihuairazo, Ecuador). Shannon index, taxonomic distinctness and species assemblage composition did not reveal deterministic and directional patterns. Only the principal coordinate analysis performed on the Antisana dataset showed that some species had a clear preference for terrains deglaciated for more than 200 years. Our results showed that equatorial glacier forelands are colonised by pioneer species that persist from the recently deglaciated terrains (less than 25 years) to terrains deglaciated since more than 200 years. This pattern fits the 'addition and persistence model' of high-latitude glacier forelands, rather than the 'species replacement model' of the Alps. The pioneer species observed are high-altitude specialists adapted to constantly cold environments, but not specifically ice-related. In the current context of climate warming, pioneer and cold-adapted species living near the glaciers of equatorial mountains are therefore only threatened by the 'summit trap' risk, unlike in temperate regions, as they are not strictly linked to the glacier microclimate.

Adipokines underlie the early origins of obesity and associated metabolic comorbidities in the offspring of women with pregestational obesity.

Maternal pregestational obesity is a well-known risk factor for offspring obesity, metabolic syndrome, cardiovascular disease and type 2 diabetes. The mechanisms by which maternal obesity can induce alterations in fetal and later neonatal metabolism are not fully elucidated due to its complexity and multifactorial causes. Two adipokines, leptin and adiponectin, are involved in fetal and postnatal growth trajectories, and both are altered in women with pregestational obesity. The placenta synthesizes leptin, which goes mainly to the maternal circulation and in lesser amount to the developing fetus. Maternal pregestational obesity and hyperleptinemia are associated with placental dysfunction and changes in nutrient transporters which directly affect fetal growth and development. By the other side, the embryo can produce its own leptin from early in development, which is associated to fetal weight and adiposity. Adiponectin, an insulin-sensitizing adipokine, is downregulated in maternal obesity. High molecular weight (HMW) adiponectin is the most abundant form and with most biological actions. In maternal obesity lower total and HMW adiponectin levels have been described in the mother, paralleled with high levels in the umbilical cord. Several studies have found that cord blood adiponectin levels are related with postnatal growth trajectories, and it has been suggested that low adiponectin levels in women with pregestational obesity enhance placental insulin sensitivity and activation of placental amino acid transport systems, supporting fetal overgrowth. The possible mechanisms by which maternal pregestational obesity, focusing in the actions of leptin and adiponectin, affects the fetal development and postnatal growth trajectories in their offspring are discussed.

Nitrogen (protein) determination in single seeds by nuclear reactions.

In this work, a brief review on nuclear reaction methods aimed at nitrogen assessment in organic matter is given, followed by a detailed application using a deuteron beam and (d,p) and (d,α) induced reactions on 14N to determine nitrogen content in single seeds This study covers the analysis of five wheat and four maize stable varieties, which showed up good (linear) correlation coefficients in comparison with corresponding Kjeldahl nitrogen analysis for each species. This method of analysis turns out to be a fast and non-destructive technique for protein determination in cereals, besides its extendibility to other plant products for human nutrition.

The Mexican consensus on the treatment of hepatitis C. / Consenso Mexicano para el Tratamiento de la Hepatitis C.

The aim of the Mexican Consensus on the Treatment of HepatitisC was to develop clinical practice guidelines applicable to Mexico. The expert opinion of specialists in the following areas was taken into account: gastroenterology, infectious diseases, and hepatology. A search of the medical literature was carried out on the MEDLINE, EMBASE, and CENTRAL databases through keywords related to hepatitisC treatment. The quality of evidence was subsequently evaluated using the GRADE system and the consensus statements were formulated. The statements were then voted upon, using the modified Delphi system, and reviewed and corrected by a panel of 34 voting participants. Finally, the level of agreement was classified for each statement. The present guidelines provide recommendations with an emphasis on the new direct-acting antivirals, to facilitate their use in clinical practice. Each case must be individualized according to the comorbidities involved and patient management must always be multidisciplinary.

The anti-CD6 antibody itolizumab provides clinical benefit without lymphopenia in rheumatoid arthritis patients: results from a 6-month, open-label Phase I clinical trial.

Itolizumab is a humanized anti-CD6 monoclonal antibody (mAb) that has previously shown encouraging results, in terms of safety and positive clinical effects, in a 6-week monotherapy clinical trial conducted in rheumatoid arthritis (RA) patients. The current Phase I study evaluated the safety and clinical response for a longer treatment of 12 itolizumab intravenous doses in subjects with active RA despite previous disease-modifying anti-rheumatic drug (DMARD) therapy. Twenty-one subjects were enrolled into four dosage groups (0·1, 0·2, 0·4 and 0·8 mg/kg). Efficacy end-points including American College of Rheumatology (ACR)20, ACR50 and ACR70 response rates and disease activity score in 28 joints (DAS28) were monitored at baseline and at specific time-points during a 10-week follow-up period. Itolizumab was well tolerated up to the highest tested dose. No related serious adverse events were reported and most adverse events were mild. Remarkably, itolizumab treatment did not produce lymphopenia and, therefore, was not associated with infections. All patients achieved a clinical response (ACR20) at least once during the study. Eleven subjects (55%) achieved at least a 20% improvement in ACR just 1 week after the first itolizumab administration. The clinical response was observed from the beginning of the treatment and was sustained during 24 weeks. The efficacy profile of this 12-week treatment was similar to that of the previous study (6-week treatment). These results reinforce the safety profile of itolizumab and provide further evidence on the clinical benefit from the use of this anti-CD6 mAb in RA patients.

Prevalence of Barrett's esophagus: An observational study from a gastroenterology clinic. / Prevalencia de esófago de Barrett: estudio observacional en una clínica de gastroenterología.

INTRODUCTION AND AIMS: Barrett's esophagus is a condition that predisposes to esophageal adenocarcinoma. Our aim was to establish the prevalence of Barrett's esophagus at our center, as well as determine its associated factors. MATERIALS AND METHODS: We retrospectively assessed the endoscopic reports of 500 outpatients seen at our Gastroenterology Service from November 2014 to April 2016. We determined the prevalence of Barrett's esophagus and analyzed the demographic, clinical, and endoscopic findings associated with that pathology. RESULTS: The prevalence of Barrett's esophagus was 1.8%. The mean age of the patients with Barrett's esophagus was 58.7 years (range: 45-70) and there was a predominance of men (66%). In the subgroup of patients with symptoms of gastroesophageal reflux (n=125), Barrett's esophagus prevalence was 7.2%. In the multivariate analysis, the factors that were independently associated with Barrett's esophagus were gastroesophageal reflux (P=.005) and hiatal hernia (P=.006). CONCLUSIONS: The overall prevalence of Barrett's esophagus was 1.8% in our population, with a prevalence of 7.2% in patients that had symptoms of gastroesophageal reflux.

Eosinophilic esophagitis. The North against the South? A bio-economic-social mechanistic approach and clinical implications. / La esofagitis eosinofílica. ¿El Norte contra el Sur? Enfoque mecanicista bio-económico-social e implicaciones clínicas.

Eosinophilic esophagitis is a chronic antigen-mediated disease characterized by esophageal symptoms, esophageal eosinophilia, and the absence of response to proton pump inhibitors. It is the most frequent cause of dysphagia and food impaction in adults. Its incidence and prevalence is very high in the developed countries (USA, Europe, Australia), where its connotation is that of an emerging epidemic. While studies have been published with large case series in the developed countries, those published in Latin America are small or consist of isolated case reports. The differences in the prevalence of the disease between the developed and developing regions are unknown. Genetic or racial causes have been cited. Nevertheless, the epidemic nature of the disease suggests that environmental causes are the most powerful. Based on the published hypotheses, as well as on epidemiologic studies, the present review discusses some of the possible causes of the disparity in the prevalence of eosinophilic esophagitis between the two types of countries. The 'hygiene hypothesis' is reviewed, together with the possible relation of Helicobacter pylori, intestinal parasites, and modifications of the esophageal microbiota in patients with eosinophilic esophagitis. In reference to studies conducted in the United States, the clinical behavior and progression of eosinophilic esophagitis in Hispanics is reviewed and a possible predominant phenotype in Mexican and other Latin American patients is discussed. Finally, based on the above, an algorithm for studying the disease in the Latin American countries is proposed.